This invention relates to animal cages such as poultry transport cages of the stacking type used for making truckload shipments of live pountry in general, and more particularly to an improved latch for such cages.
As described in my previous U.S. Pat. No. 3,754,676 issued Aug. 28, 1973, poultry is usually shipped in rectangular cages each holding six chickens for purposes of convenience in handling and to minimize injury. In that patent, I described and claimed an improved molded plastic rectangular cage which had an enlarged rounded access opening for easier loading and unloading with reduced likelihood to injury to poultry. The cage described therein meets the size, weight and strength requirements for cages in the contemplated service. In other words, it is capable of supporting a standing man, as is necessary when loading and stacking a plurality of these cages. The described cage includes a gridwork structure including lateral and longitudinal beams necessary for strength. Furthermore, it includes enlarged longitudinal beam members in combination with lateral cross beam members to define the lateral and longitudinal boundaries of an access opening in the top. Each longitudinal beam member is offset outwardly for at least a portion of the access opening to provide a widened and approximately rounded opening.
A complementary lid hinged to one of the beam members fits within the access opening so that its top surface is substantially flush with the top of the cage structure. Lid supporting flanges extend at an angle across each corner of the opening to further round the access opening without substantially reducing its useable area. Also described was a preferred embodiment made up of two identical cage halves of molded plastic joined together by metal or plastic fasteners to form a complete cage. As described, the lid member was pivotally mounted to a transverse beam member using plastic hinges so that it fitted within the access opening formed at the top of the cage. The lid was held in the closed position by means of an integrally molded latch member. The latch member comprised a rectangular portion joined on three sides to corresponding edges of a rectangular cutout portion on the lid. At each end the rectangular portion was joined to the lid by plastic torsional hinge tabs and at one side was joined to the lid by an S-shaped plastic spring to permit limited rotation about the axis of the torsional hinge tabs. A bevelled lip was contained on the other side to catch under the bottom of the lateral beam member of the top for locking engagement therewith. Opening was accomplished by pulling up on the side of the rectangular portion attached by means of the S-shaped plastic spring member.
Although this arrangement offers the advantages of integral molding of the latch and the lid it has been found to suffer from disadvantages. The latch is not particularly easy to operate and the torsional members and spring are subject to breaking as they become fatigued. When such occurs this requires the replacement of the complete lid. In view of these difficulties, the need for an improved latch for the lid of a poultry cage of this nature becomes evident.